A method is proposed to calculate the bending error of light passing through the Earth’s atmosphere at any observation height and in the range of 0– \(90^{\circ }\) from apparent zenith. Assuming that the Earth’s atmosphere is in accordance with the spherically symmetric structure, the Earth’s atmosphere is stratified according to the constant height \(\Delta h\) , and the atmospheric parameters such as temperature and pressure obtained based on NRLMSIS 2.0 are used to calculate the atmospheric refractive index at each layer. The e-index model of refractive index is obtained by nonlinear least square regression, and the gradient of refractive index at any position is obtained. Using Snell’s law applied to spherical atmosphere, the zenith distance of light at each layer is obtained. Finally, combined with the above parameters, the trapezoidal rule is used to calculate the refraction integral numerically, and the bending error of light is obtained. The feasibility and reliability of the proposed method are proved by comparing with previous studies.
